Legaia 2: Duel Saga is the PS2 sequel to the 1999 RPG, Legend of Legaia, featuring a new world and cast of characters. Players become a rookie "Mystic" named Lang as he embarks on a journey to retrieve his village's precious water crystal following its theft at the hands of a mysterious man named Avalon. Lang will gain the assistance of four allies as he unravels a larger scheme.

Like the first game, a major selling point of Legaia 2 is the Tactical Arts System which factors heavily in the turn-based combat system. Instead of a standard attack action, players input a series of attacks incorporating punches and kicks to unlock and execute powerful Arts techniques; as characters gain experience, they can input longer strings of attacks and execute multiple Arts each turn. Magical attacks meanwhile come from Origins, spirits that only Mystics can summon to aid them in combat.

Players can also craft weapons, tools and items by combining old ones to create more powerful replacements.